﻿/*******************************************************************************************
 * Copyright (c) 2009 Alex Robson, Rob Simmons, Craig Israel, and Rachel Twyford
 *
 * Use of this software in any form requires that you have both 
 * read and agreed to the following terms:
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the "Software"), 
 * to deal in the Software without restriction, including without limitation 
 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions: 
 *
 * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright notice, 
 * this list of conditions and the following disclaimer in the 
 * documentation and/or other materials provided with the distribution.
 * Neither the name of Nvigorate nor the names of its contributors may 
 * be used to endorse or promote products derived from this software without 
 * specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY
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 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
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 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Linq;
using Nvigorate.Common;
using Nvigorate.Common.Reflection;
using Nvigorate.Relational.Mapping.Interface;
using Nvigorate.Xml;

namespace Nvigorate.Relational.Mapping
{
    public abstract class BaseAssignmentRelationship : IRelateOneToMany<IAssignmentPoint>, ILinqToXml
    {
        protected Dictionary<IAssignmentPoint, IAssignmentPoint> _constraints;

        protected Relationship _relationship;

        protected string _relative;

        protected Type _relativeType;

        protected string _subject;

        protected Type _subjectType;

        protected string _relationSource;

        protected string _relativeProperty;

        /// <summary>
        /// Defines how the subject and relative relate to one another
        /// </summary>
        public Dictionary<IAssignmentPoint, IAssignmentPoint> Constraints
        {
            get { return _constraints; }
        }

        /// <summary>
        /// Describes the nature of the relationship from the
        /// perspective of the subject
        /// </summary>
        public Relationship Relationship
        {
            get { return _relationship; }
            set { _relationship = value; }
        }

        /// <summary>
        /// Identifies the source name that contains the relationship
        /// row for many-to-many relationships
        /// </summary>
        public string RelationSource
        {
            get { return _relationSource; }
            set { _relationSource = value; }
        }

        /// <summary>
        /// The name of the relative
        /// </summary>
        public string Relative
        {
            get
            {
                _relative = _relative ?? _relativeType.FullName;
                return _relative;
            }
            set { _relative = value; }
        }

        /// <summary>
        /// The name of the property in which the
        /// relative is stored
        /// </summary>
        public string RelativeProperty
        {
            get { return _relativeProperty; }
            set { _relativeProperty = value; }
        }

        /// <summary>
        /// The name of the relative type
        /// </summary>
        public Type RelativeType
        {
            get
            {
                _relativeType = _relativeType ?? Reflector.GetType(_relative);
                return _relativeType;
            }
            set { _relativeType = value; }
        }

        /// <summary>
        /// The name of the subject
        /// </summary>
        public string Subject
        {
            get
            {
                _subject = _subject ?? _subjectType.FullName;
                return _subject;
            }
            set { _subject = value; }
        }

        /// <summary>
        /// The name of the subject type
        /// </summary>
        public Type SubjectType
        {
            get
            {
                _subjectType = _subjectType ?? Reflector.GetType(_subject);
                return _subjectType;
            }
            set { _subjectType = value; }
        }

        public virtual bool IsInverse(ITargetRelationship relationship)
        {
            var candidate = relationship as BaseAssignmentRelationship;
            if(
                SubjectType == relationship.RelativeType &&
                RelativeType == relationship.SubjectType &&
                Constraints.All(c => candidate._constraints[c.Value] == c.Key)
                )
            {
                return true;
            }
            return false;
        }

        #region ILinqToXml

        public XElement GetXElementRepresentation()
        {
            return new XElement("relationship",
                                new XAttribute("type", _relationship),
                                new XAttribute("subject", _subject),
                                new XAttribute("relative", _relative),
                                GetElementForDictionary()
                );
        }

        private List<XElement> GetElementForDictionary()
        {
            return _constraints.Select(kvp =>
                                       new XElement("constraint", 
                                                    new XAttribute("subjectTable", kvp.Key.Entity),
                                                    new XAttribute("subjectField", kvp.Key.Field),
                                                    new XAttribute("relativeTable", kvp.Value.Entity),
                                                    new XAttribute("relativeField", kvp.Value.Field)
                                           )).ToList();
        }

        public object ParseXElement(XElement element)
        {
            _relationship = (Relationship) Enum.Parse(typeof (Relationship), element.GetAttributeValue("type") ?? "Parent");
            _subject = element.GetAttributeValue("subject");
            _relative = element.GetAttributeValue("relative");

            _constraints = element.Elements().Select(e =>
                {
                    var subject = new AssignmentPoint(e.GetAttributeValue("subjectTable"), e.GetAttributeValue("subjectField"));
                    var relative = new AssignmentPoint(e.GetAttributeValue("relativeTable"), e.GetAttributeValue("relativeField"));
                    return new KeyValuePair<IAssignmentPoint, IAssignmentPoint>(subject, relative);
                }).ToDictionary(kvp => kvp.Key, kvp => kvp.Value);

            return this;
        }

        #endregion
    }
}